Semiconductor devices are built in semiconductor materials, typically silicon wafers (or substrates), through a series of processes. These processes modify the silicon wafer by building components of the semiconductor devices in the wafer using a variety of materials, including conductive materials, insulating materials, and semiconducting materials. Many of the processes to build these components involve the use of thermal treatments that work to overcome the activation energies that govern the processes. These activation energies determine the rate of construction or modification of the components using the respective thermal treatment.
One such thermal treatment is rapid thermal processing (RTP). In RTP, suitable silicon substrates are heated rapidly to achieve target temperatures using lamp based systems, such as halogen based lamp systems. The rate of heating and the time duration at the target temperature are tailored to each process based on the activation energy of the process. Generally, RTP processes are applied for a time duration on the order of 1 second. Applications of RTP include the formation of salicide layers on the source and drain regions of a transistor.
Other forms of thermal treatments include flash and laser annealing processes, which employ shorter time periods than RTP anneals, often on the order of milliseconds to microseconds. Thermal treatments, such as RTP, flash annealing, and laser annealing enable tailoring of thermal budgets to process specific requirements, such as activation energies.
The Figures illustrate some specific aspects of the RTP methods and associated apparatus for carrying out such methods. Together with the following description, the Figures demonstrate and explain the principles of the RTP methods and associated apparatus for carrying out such methods. In the drawings, the thickness of layers and regions are exaggerated for clarity. It will also be understood that when a layer is referred to as being “on” another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may also be present. The same reference numerals in different drawings represent the same element, and thus their descriptions will not be repeated.